Abrading pencil



E. R. CO NNERS ABRADING PENCIL Original Filed Sept. 6, 1921 Nov. 24 1925- J NYENTOR.

Patented Nov. 24, 1925.

UNITED STATES PATENT OFFICE.

EDWARD R. CONNERS, OF'CINCINNATI, OHIO, AS SIGNOB TO THE PRECISION TRUING MACHINE AND TOOL COMPANY, OF CINCINNATI, OHIO, A CORPORATION OF OHIO.

ABRADING PENCIL.

Application filed September 6, 1921, Serial No. 498,732. Renewed October 16, 19245.

To ail whom it may concern:

Be it known that I, EDWARD R. CoNNnRs, a citizen of the United States, residing at Cincinnati. in'thecounty of Hamilton and State of Ohio, have invented certain new and useful Improvements in Abrading Pencils, of which the following is a specification.

Mv invention relates to abrading pencils similar in character to those shown and described in my co-pending applications for Letters Patent on devices for truing and dressing grinding wheels, Serial No. 366,970, filed March 18. 1920, issued as Patent No. 1,395,392, dated November 1. 1921, and on mechanism for truing and dressing grinding whee-l, Serial No. 415.403, filed October 7, 1920, issued as Patent No. 1,395,394, dated November 1, 1921, and is an improvement upon the abrading pencils therein disclosed.

A usual means heretofore employed in truiug and dressing grinding surfaces of grinding wheels has been a diamond tool, comprising a diamond, made to contact the grinding surface of the grinding wheel, but diamonds have become very scarce and very expensive, and it is one of the objects of my invention to dispense with the use of the same.

It is the object of my invention further to provide a rotatable abrading stub or pencil, hereinafter called a pencil, so positioned that its axis of rotation is presented toward the grinding wheel with which it is to coact for the purpose of truing or dressing, and with novel means for insuring correct positioning of the same; further, to provide a rotatable abrading pencil arranged to make end-contact, preferably with a substantially frusto-conical end abradin face, with the grinding surface of the grinding wheel, or, to provide a rotatable abradinq pencilfor the purpose mentioned which has an endcontact face surrounding a center space which is coincident with the axis of rotation of the rotatable abrading pencil, andto pro vide such devices with a securing part which isdefinitely conce-ntric.to the axis of rotation of said .rotatable abrading pencil, concentric to the apex of the frusto-conical abrading face: whenemployed, and concentric to said center space.

It is the object of my invention further to provide a rotary abrading pencil preferably of materially'less diameter than thediameter of the grinding wheel with which it coacts, and having an axis of rotation presented toward the grindin wheel to be trued, and acting with a swirling abrading motion on the rotatinggrinding wheel, for truing and dressing the same, and to provide said rotary abrading pencil with a securing peripherytruly concentric with its axis of rotation.

As heretofore explained in my aforementioned copending applications, I prefer to provide a rotary'truing orv dressing abrading pencil which is of a texture much harder than the texture of the grinding wheel to be true'd or dressed. I have found it possible to produce abrading pencils of excep-v tional hardness and durability. I have found, however, thatdue to the extreme heat and pressure employ ed in forming such pencil, it is difficult to control concentricity of its-periphery with the axis of its bore, and difficult to produce such pencil with a periphery at its end arranged to be grasped so firmly in holding devices as to securely hold the abrading pencil and cause-proper rotation of the abrading end of the pencil. I have overcome these objections and difficulties by my improved device.

The invention -will be further readily understood from the following description and claims, and from the drawings, in which latter;

Fig. 1 represents a side elevation of an abrading pencil in its crude form.

Fig. 2 is a 'side elevation of an abrading pencil showing one end thereof provided with a rabbet for the reception of a truing ring and its other end provided with a frusto-conical, end abrading face.

Fig. 3 is an end elevation of the same viewed from the attaching end.

Fig. 4 is an axial section shown in an exemplifiedmold.

Fig. 5 is an axial section of device in completed form.

Fig. 6 is a perspective View of my improved device, in connection with an exemplifying truing device, shown in axial section on the line 66 of Fig. 7, and in coactive my improved relation in-an exemplifying grinding Ina-- chine, artly broken away; and

Fig.2 is across-section of the same, when on the line 7-7 of Fig; 6.

The abrading pencll inan exemplif ing form is shown at 11. It is of'e'xtremely ard of the I same substance, preferably much harder than the hardness of the grinding wheel, shown at 12, of the grinding machine. The abrading pencil acts on the grinding face 15 of the grinding wheel. The tail-stock of the grinding machine is indicated at 16, the tail-center at 17, and the rotating work at 18, rotated in suitable manner, or as shown and described in my aforesaid copending applications.

The abrading pencil may for instance be a carborundum product produced under extreme heat, for instance under the heat of an electric arc, and of granular structure, and be formed under great hydraulic pressure, the grains 21 being fixedly bound together in the structure and forming a surface having interstices 22, which may also be termed recesses or pores, therein. (See Fig. 5) The texture of the abradlng pencil is preferably coarser than the texture of said grinding wheel.

I have in Fig. 1, at 25, shown the abrading pencil in its crude form as it is received from the hydraulic press and furnace L in one of the forms in which I prefer to produce the same, although if desired, the same may be produced with one of its ends reduced in diameter, as shown at 26 in Fig. 2.

The pencil, owing to the intense heat to which it has been subjected, the hardness of its ingredients, and the hardness to which it has been reduced while being formed, is liable to be warped, to be uncertain in'its crosssectional dimensions and form, and in the axial alinement of-its parts. The cross sectional irregularities or the irregularities in axial parallelism are unimportant as far as the abrading action upon the grinding wheel is concerned, provided that the abrading pencil is securely held so as to prevent shifting or wobbling while in operation and so that its physical axis shall be substantially coincident with its axis of rotation.

For providing these latter conditions, I provide one end of the abrading pencil with a ring 28, whose outer )eriphery is concentric with the mesne physical axis of the abrading pencil, so that, when the ring is fixed in a rotatable holder, exemplified as a chuck 29, the abrading pencil will rotate with its physical axis substantially coincident with its axis of rotation.

The ahrading pencil further, while being formed, is preferably provided with an axial bore 30. Thus formed, the abrading encil is a cylindrical abrading body provide with a central or :axial space. The axis of a pencil of this character, which is coincident with its axis of rotation, is a neutral point, that is to say, a non-rotating point. In the absence of the axial bore, the pencil would form a point at-its axis unduly protruding in axial direction, due to lack of wear thereon, and would form a point liable to gouge into or form detrimental marks or scores in the grinding wheel. To avoid such detriment and to provide a pencil which will produce an even surface upon the grinding wheel, I provide the central space or axial bore referred to.

I prefer to provide one end of the body of the abrading pencil with a rabbet 32, in

rotation is at an angle at one side of a right angle to the axis of rotation of' the grinding wheel, as exemplified in Fig. 6, or at an angle to the vertical plane in which said right angle is located, or so that said axis of rotation is located in said vertical plane at an angle to a radial line of the grinding wheel,

whereby its axis of rotation is a chord to the circle of the grinding wheel, or in a direction including both said angles.

' Suitable rotation is imparted to the grinding wheel and to the work, the directions of rotation of the same being indicated respectively by the arrows a and b. In the present exemplifi-cation, the abrading pencil is normally at rest and rotation is imparted thereto, in the direction of the arrow 0, by contact at one side of its axis of rotation with the grinding wheel. 1

Movement lengthwise of the axis of rotation of the grinding wheel is caused between the grinding wheel and the abrading pencil, as well as between the grinding wheel and the work, preferably for causing alternate contacts between the work and the abrading pencil on the one part and the grinding wheel on the other part, all as more fully explained in my' aforesaid copending applications.

In the present exemplification, the ring the abrading pencil and to hold the abrading pencil so that its mesne axis is coincident with its axis of rotation. Other characters of chucks and holding devices may also be employed to hold or support the ahrading pencil.

end of the abrading pencil is received in The chuck 29 is secured to a shaft 38, as by a pin 39, the shaft rotating suitably in a barrel 4(), rotation of the shaft and of the abrading pencil being maintained between intervals of contact of the abrading pencil with the grinding wheel, by means of a fly-wheel 41, fixed to said shaft, and rotating in an enlargement 42, forming a cup received over the fly-wheel, a cover-plate 43 closing said cup. A bushing 45, is located in the barrel and is fixed therein by a set-screw 46. Ball-bearings 47, 48, are located at the respective ends of the bushing, these ball-bearings being combined radial and end-thrust bearings.

The barrel is secured relatively to the grinding Wheel, as by providing a clampbearing 51 received about the barrel. The barrel may be adjusted axially in said clamp-bearing. A clamp 52 is secured about the tail-center 17, the clamp and clampbearing being connected by an arm 58, so arranged as to present the end of the abrading pencil at proper "angle to the grinding surface of the grinding wheel.

The movement between the contact or impinging portion of the rotary abrading pen cil and the grinding surface is preferably a swirling movement at the line of contact, due, for instance, to the variations of distance along said line of contact from the axis of rotation of the abrading pencil, resulting in a wiping etl'ect of the abrading pencil on the grinding surface, for wiping or-drawing out the grinding offal from the interstices or pores of the grinding surface, and acting, throughout a portion of its contact-line, on the grains of the granular grinding surface with a motion different from the direction of grinding motion of the grinding surface upon the work, for sharpening the grains of the granular grinding surface.

The rotary abrading pencil is of coinparatively small diameter with relation to the dian'iete'r of the grinding wheel and is arranged to make substantial end-contact with said grinding wheel in such manner that this end-contact shall preferably be at one side only of said axis of rotation, Whereby the end-contact surface of the-rotary abrading pencil is substantially frusto-conical.

In order that such relations of motion between the abrading pencil and the grinding surface of the grinding wheel shall be true relations, I provide the ring arrangement for the securing endof the abrading pencil. The abrading pencil may be placed in a suitable mold 55. The abrading pencil is placed in the mold with its mesne axis coincident with the axis of the mold. The diameter of the mold may be greater than "the diameter of the abrading pencil to allow for variations in the latter, the space between the abrading pencil and the Wall of the mold being provided with a filling 56, as of molders clay. The arrangement forms an annular space 57 between the reduced end 26 of the body of theabrading pencil and the Wall 58 of the'mold.

A core 59, shown as a stem, is placed in the bur-e30 so as to be coincident with the axis of the mold. Flowable metal is then caused to flow into the mold into said annular space to form the ring, the metal also preferably being received across the end of said reduced end of the abrading pencil to form a flange 60, whereby a cap is formed, having a central hole 61 coincident with the bore of the pencil, to form a clearance Space for the bore, through which refuse due to the abrading may pass.

The fiowable material employed is preferably one which is readily received-in the interstices, recesses or pores in the outer periphery of the reduced end of the pencil and in the end of the latter, so as to form an intimate and non-yielding connection between said ring or cap and the body of the abrading pencil. The metal, upon cooling, shrinks about the body of the abrading pencil for more intimate connection therewith. I have found a desirable metal of this character' to be lead or lead composition which will readily flow into the interstices in the surface of the abrading pencil to form close and rigid union therewith. The ring pref erably forms protuberances 62 in the recesses and pores. The protuberances or projections of the metal received in the inter-- stices in the periphery of the reduced end of the abrading pencil, in the shoulder 63 at the end of the rabbet 32, and in the end of saidreduced end when a cap is employed, act counter to each other in rigidly fixing the ring or cap in place.

The periphery of the ring and end of the cap may, if desired, be suitably trued with. suitable tools, as by turning, to bring the same into trued relation with the axis of rotation of the abrading pencil. A positioning of the rotary abrading pencil so that its axis of rotation is proximate to a line radial to the axis of rotation of the grinding wheel and at right angles to the latter axis, will result in a dressing of the grinding wheel with a finer surface, whereas, if the rotary abrading pencil is positioned with its axis of rotation describing a chord to the circle of the grinding wheel or at an angle to the vertical plane in which said right angle is located, the grinding surface will be trued or dressed with a coarser surface, the degree of coarseness depending on the degree which the axis of rotation of the abrading pencil departs from a radial position. The accuracy of the truing or dressing operation is dependent on the rigidity with which the abrading pencil is held in its intended or'true path of rotation and this latter is determined or assured by the employment of my invention.

By the employment of my invention, accuracy of the truing and dressing Operation is assured, and a great saving in the durability of the grinding surface is accomplished, and effectiveness of the grinding wheel is enhanced.

Having thus fully described my invention, What I claim'as new, and desire to secure by Letters Patent, is:

1. An abrading pencil having a short body of extreme hardness provided with an exposed cylindrical outer periphery and an axial bore, said cylindrical outer periphery and said bore being concentric, and a short band of softer material cast about the end of said'short body 'and having' a cylindrical outer periphery concentric with said firstnamed cylindrical outer periphery, said short band of softer material being of substan-v tially less length than the length of said ex-' posed cylindrical outer periphery, and constructed and arranged for having a chuck provided with jaws concentric about said band in axial alinement with a shaft to which said chuck is secured.

2. An abrading pencil having a body of extreme hardness provided with a cylindrical outerperiphery, an axial bore and a reduced end having a reduced cylindrical outer periphery, said cylindrical outer peripheries and said bore being concentric and a band of softer material cast about said reduced cylindrical outer periphery and having a cylindrical outer periphery substantially equal in diameter with the diameter of said firstnamed cylindrical outer periphery and concentric therewith.

3. An abrading pencil having a body of extreme hardness provided with a cylindrical outer periphery and an axial bore con.

centric with said cylindrical outer peripliery, and a cup-shaped band 5f softer material cast about an end of said body and comprising an end flange cast upon the butt end of saidbody to form a cup-shaped ferrule having a cylindrical outer periphery and provided With an axial bore connecting with and in line with said first-named axial bore, and said bores in said body and said ferrule forming a passage for refuse due" to the abrading.

4. In combination, an abrading pencil having abody of extreme hardness provided with a cylindrical outer periphery, anaxial bore and a reduced end having an outer periphery, said first-named outer periphery.

and said bore being concentric, and a cupshaped band of soft material comprising a ring portion received in the lateral space between said reduced end and the cylinder extended of said cylindrical outer periphery and an end flange cast-upon the butt end of said reduced end, and provided with an axial boreconnected with and inline with said first-named bore, and said cup-shaped band having a cylindrical outer periphery concentric with said first-named cylindrical outer periphery, for the purpose described. In testimony whereof, I have hereunto signed my name.

' EDWARD R. CONNERS. 

